The invention relates to lasers, and more particularly to carbon dioxide lasers of the fast axial flow type.
Fast axial flow carbon dioxide lasers are known. Their principal advantage over crossflow type carbon dioxide lasers is greatly increased efficiency, usually about double that of crossflow lasers.
Construction of fast axial flow lasers is generally somewhat more complex than that of the crossflow type, primarily due to the manner in which the flowing gas must be conducted through the discharge tubes.
One problem with fast axial flow carbon dioxide lasers has been the difficulty in creating a uniform distribution of electrical discharge in each tube to avoid gain inhomogeneity and loss of efficiency and power in the laser beam. Prior art systems often resorted to elaborate and complex gas distribution apparatus.
Another problem in the prior art which contributed to loss of efficiency and power was thermal instability in the mounting of the mirrors, particularly with regard to maintaining constancy of mirror separation distances and angular alignment with wide changes in temperature.
Prior art fast axial flow systems usually included a plurality of tees for delivering and receiving exhaust gas from the discharge tubes and for conducting the gas ultimately to a heat exchanger. Gas flow was toward the center, isolating the optics from hot exhaust, but with several tee junctions in succession. Such systems tended to be bulky.
Mirror mounting, particularly where the mirror must be cooled and must be capable of removal for maintenance or replacement, has also been a problem in previous systems.
It is among the objects of the present invention to overcome these problems and shortcomings of the prior art, with an efficient, versatile, sturdy and compact construction of a fast axial flow carbon dioxide laser as described below.